Fuel control means



Aug. 9, 1938. M. CHANDLER 2,125,835

FUEL CONTROL MEANS Filed Feb. 1, 1937 ,2 Sheets-Sheet 1 /7/L ra/v 1 Oar/w; 5e INVENTOR' ATTORNEY Aug. 9, 1938. M. E. CHANDLER 2,125,886

FUEL CONTROL MEANS Filed Feb. 1, 1957 2 Sheets-Sheet 2 1 m Ll:

/7/u-a/Y E Cv/PNALEE INVENTOR BY 6 Z TTORNEY Patented Aug. 9,1938

UNITED STATES PATENT OF ICE rum. con'rn'or. mums Milton a. Chandler, Detroit, Mich. Application l 'ebruary 1, 1937, Serial No. 123,359

6 Claims. (Cl. 201-41) This invention is an improvement on the carburetor shown in the Milton J. Kittler application, Serial No. 107,386. In a carburetor of this type it is desirable that the mixture ratio be richer at maximum power than it is under throttle, because the engines to which these carburetors are applied are built so close to their safety limit that unless excess fuel is used, the engines fail because under the excessive heat the strength of the parts subjected to the heat is re- As pointed out in the above case, the mixture v ratio does not vary appreciably with altitude. Hence the applicant has discovered that if he utilizes the rate of flow of fuel to the carburetor he can control the additional fuel by a device controlled bythis flow End thereby obtain a definite percentage increase -in the mixture ratio.

- other words, if the mixture ratio is correct, that is to say, gives a uniform mixture regardless of throttle position or altitude, then a definite deviation from this theoretical mixture for practical purposes can also be controlled by the flow and the percentage increase will be uniform regardless of variations in altitude.

In the drawings:

Figure 1 shows a cross sectional elevation taken on plane l-l of Figure 2.

Figure 2 shows a cross sectional elevation taken on plane 2-2 of Figure 1.

Figure 3 shows a modification of the novel con another modification of the B isl the fuel entrance chamber in which is 10- 4 cated the flexible metal bellows C supp t by a helical spring D. This spring is mounted on the cover E which engages with the body F of the control device. A passage G in the body]? connects the interior of the bellows C with the throat '45 of a venturi J. This throat is sufllciently restricted so that a definite number of inches of mercury depression is created and transmittedthrough the pipe G tothe interior of the bellows C. The restriction, however, is not sufficient to to create anflappreciable resistance to the flow of gasoline through J. The gasoline flows through J to the pressure reduction valve L to the diaphragm chamber M through which it dischargesunder a constant head of relatively low value into the passage N, the flow through which is controlled by the needle valve U which is moved in unison with the throttle valves V, V. The core rugated bellows C carries a needle valve P which serves to cut off the connection between the fuel chamber B and a fuel passage Q and also to regulate the flow therethrough. This passage Q communicates with an air passage R which is connected to the air entrance ,8. A fuel passage T in the nozzle bar 0 serves as the fuel outlet from the passage Q into the mixing chamber between the throttles V, V. The mixture of fuel and air controlled by the needle valve U discharges through the openings X into the mixing chamber. When the throttle is closed, a little air is admitted through the annulus A which derives its air from the air entrance S through the center of the hollow needle U. 1

A chamber Y is located on one side of the diaphragm and communicates through the pipe K with the mixture chamber through the interior of the nozzle bar 0. A valve Z controls the connection between the chamber Y and the outlet X so as to modify the pressure in the diaphragm cham-- ber by the nozzle suction. 'The chamber Y is also connected through the tube I with the air entrance S. The valve Z is so designed that the chamber Y can communicate with the air entrance S through the pipe I and with mixing chamber through the openings X, X or with both the air entrance 3 and with the nozzle suction at X. The opening of the needle valve U is controlled by the movement of the throttles V, V through the linkage VI, V2. v l

Operation The operation of the engine proceeds ina normal way until the flow through the venturiJ reaches a predetermined value and when the depression therein is sufficient to overcome the spring D and the needle valve P is opened. When the needle valve P opens fuel flows from the fuel regulating chamber W to the passage Q under the pressure of fuel in thefuel pump H. Additional fuel is therefore discharged through T into the mixing chamber. As the pressure in chamber, W runs from four to seven pounds per square inch, the flow through T is determined by-the pressure in chamber W and the opening around the needle valve P rather than by the flow of air from the air entrance S through the passage R into the fuel outlet T. In other words, theadditional fuel admitted at T is controlled solely by the quantity of fuel flowing through the venturi J and the absolute pressure of the fuel from the fuel pump. The result is that when the engine is opened up and the horsepower developed reaches a critical value, a definite amount of excess fuel is admitted through the opening T and the tendency of the engine to burn up is counteracted by the cooling effect of the additional fuel admitted through the opening T, which addition is proportional to the normal flow. By making the mixture excessively rich, it is possible to develop an extra 20% in power. The extra fuel produces a lower engine temperature and thus prevents the engine overheating.

In Figure 3 the spring Dis supported by a sylphon bellows DI so that as the altitude increases the spring D becomes compressed and hence the opening of the needle valve P is reduced.

In Figure 4 a sharp edged orifice J is substituted for the venturi J.

The diaphragm chamber M is shown located so that its center is higher than the passage N. In the Kittler case referred to above, it has been found advantageous to locate the passage N above the chamber M, but the drawings in this case were made diagrammatically to illustrate the feature shown by the parts B, C, D, E, F, G, J, and P, and this device is not restricted to carburetors in which the mixture ratio remains substantially constant at altitudes.

What I claim is:

1. In a carburetor having a source of fuel supply under substantially constant pressure, a fuel supply chamber connected thereto, a pressure reducing valve therefor adapted to maintain a relatively low pressure of constant value in said chamber, a fuel outlet passage from said chamber adapted to discharge into said carburetor, a second fuel passage connecting the high pressure fuel directly to the carburetor, a second fuel valve in said passage, and means responsive to the flow of gasoline from the high pressure fuel inlet to the pressure reducing valve for operating said second valve for the purpose described.

2. In an internal combustion engine, the combination with a throttle controlled air inlet, of two fuel nozzles having restricted orifices arranged to discharge into said inlet adjacent to said throttle, a mechanically operated fuel pump for supplying liquid fuel to said nozzles, means controlled by the throttle for varying the area of the discharge orifice of one of said nozzles, and means actuated by the rate of fiow through said orifice for controlling the area of v the other orifice.

3. Fuel control means for an internal combustion engine carburetor comprising, a source of fuel supply having a substantially constant pressure, a fuel passage leading to said carburetor, a secondfuel passage also leading to said passage, a restriction in the first mentioned passage, a regulating valve in the second passage; means responsive to the depression created by said restriction for opening said valve for the purpose described.

4. Fuel control means comprising a source of fuel under a substantially constant pressure, a fuel passage leading therefrom to said carburetor, a restriction venturi-shaped in said passage, a second passage leading to said carburetor,

a regulating valve in said passage, a chamber having a flexible wall exposed on one side to the fuel pressure, a passage connecting the other side of the flexible wall to the throat of said venturi, a connection from said flexible wall to said valve, and yieldable means for closing said valve in opposition to the suction created in the throat of said venturi.

5. In a carburetor having a mixture chamber of venturi form, a fuel nozzle discharging therein, a source of fuel supply connected thereto, a second fuel nozzle'discharging into the mixture chamber, a valve controlling the flow to said second nozzle, and means responsive to the flow to the first nozzle for opening said valve.

6. In a carburetor, a mixing chamber, a fuel nozzle discharging therein, a source of fuel supply connected thereto, a second fuel nozzle also connected to said source of fuel supply, a valve controlling the flow to the second nozzle, and means responsive to the fiow to the first nozzle for controlling the valve.

MILTON E. CHANDLER. 

